A conventional turbine wheel comprises a rotary axle provided with a plurality of outwardly extending turbine blades. An arrangement is shown in U.S. Pat. No. 2,335,817 issued Nov. 30, 1943 to M. I. Topolav. In order to operate such an arrangement, one of the sets of blades, usually the upper set, is exposed to current flow and the lower set of blades is shielded from current flow to permit rotation of the wheel. However, even though the lower blades are shielded from direct current flow, they are required to move against the pressure of the water surrounding the turbine wheel such that there is a resistance to wheel rotation and a limitation on the efficiency of the turbine wheel. Therefore, by means of reducing the water resistance to the turbine wheel rotation, its efficiency will be proportionately increased.
Accordingly, the turbine device of the present invention has been designed to operate more efficiently than the prior art structures and, more specifically, has been provided with turbine blades adapted to provide a maximum driving force when exposed to current flow and to have minimal resistance to the pressure of water surrounding the wheel when in a current flow shielded position. As such, the turbine device of the present arrangement comprises a turbine bed and a turbine wheel mounted in fixed relation with respect to the turbine bed. The wheel includes a central axle and a plurality of turbine blades extending outwardly from the axle. The turbine bed is contoured to snugly accommodate and permit rotation of the turbine wheel and includes a forward shield positioned to permit current flow on the turbine blades which are in an exposed position for driving the turbine wheel and to prevent current flow on the turbine blades which are in the shielded position.
The turbine blades are made up of a plurality of sections, i.e., sections extending outwardly from the rotational axis of the turbine wheel. The sections in each blade are connected to one another by hinges. The interior section may either be fixedly or hingedly connected to the central axle. The arrangement is one in which the hinges are pressure actuated for automatic extension of the sections to the upward current flow exposed position to maximize the driving force on the wheel and pressure actuated for automatic collapse or folding of the sections when in the downward current flow shielded position to minimize resistance to wheel rotation.
This invention may also be used in conjunction with a floating water wheel, for example of the type shown in U.S. Pat. No. 2,097,286 to McGee.